This application is not related to any pending United States or international patent application.
This application is not referenced in any Microfiche Appendix.
The disclosure herein is for a system, and a method of operating a system, for separating a liquid component from a gas stream in which the liquid component is immisciblexe2x80x94that is, it is not absorbed in the gas.
The invention generally relates to gas/liquid separators which are typically process vessels that are commonly pressurized. The function of the separator system is to segregate immiscible phases of the process stream. Where the process stream is in the form of a gas stream that carries with it immiscible liquid components, the function of the separator is to separate out the liquid components to provide, at the output of the separator, a gas stream which has relatively less entrained liquid. Separators for separating liquid and gas components of the stream are commonly utilized in the oil and gas industry, specifically in oil and gas production, oil refining and gas processing. In addition, gas/liquid separators are utilized in the mining industry, chemical plants, wastewater treatment, pulp and paper plants and pharmaceutical plants.
Separators can be designed to separate: (1) two-phase streamsxe2x80x94that is, vapor/liquid streams; (2) three-phase streamsxe2x80x94that is, vapor/ organic liquid/aqueous streams; or (3) four-phase streamsxe2x80x94that is, vapor/organic liquid/aqueous-liquid/solids.
Industry has developed many types of separators. Most separation depends ultimately on the force of gravity, either natural gravity or created gravity forces such as represented by cyclone separators. Natural gravity is usually accomplished by flowing a stream having immiscible components into a vessel which provides a relatively quiescent environment that allows gravity to act on heavier components of the stream and move them into a downward part of the vessel and accordingly, forcing the lighter components into an upper part of the vessel. Artificial high gravity fields are provided by cyclone separators wherein the stream is subjected to rapid rotation. One type of artificial gravity separators is called a xe2x80x9cmono-tube cyclone separatorxe2x80x9d which utilizes an elongated tube as a rotation chamber, rotation of the stream being accomplished by means of a vortex generator, sometimes referred to as a xe2x80x9cspin generatorxe2x80x9d.
A separation system wherein artificially induced gravity is used for augmenting separation in a single tube is commonly referred to as a xe2x80x9cmono-tubexe2x80x9d cyclone separator. Separators that have one or more of the mono-tube cyclone separators enclosed within a vessel are commonly referred to as xe2x80x9ccyclone-tube separatorsxe2x80x9d. The disclosure herein relates to a cyclone-tube separator.
For background information relating to the general subject matter of this invention reference may be had to the following previously issued United States patents:
A system is provided for separating an entrained immiscible liquid component from a gas stream. The system employs a vessel. The interior of the vessel is in communication with a wet gas inlet, a gas outlet and a liquid outlet. The term, xe2x80x9cwet gasxe2x80x9d means the inlet gas stream having a liquid component or components.
At least one vortex tube is supported within the vessel interior. The vortex tube has an inlet end and an outlet end and a tubular wall having an internal surface through which gas passes. The vortex tube(s) are arranged within the vessel so that the wet gas entering the vessel flows through the vortex tube as the gas passes between the vessel wet gas inlet and the gas outlet.
A vortex generator (sometimes referred to as a xe2x80x9cspin generatorxe2x80x9d) is supported within the vortex tube near the tube inlet end. The vortex generator causes gas flowing within the vortex tube to rotate rapidly to thereby impart artificial gravity to the stream. This rapid rotation of the gas stream causes the liquid component to be forced against the interior wall of the vortex tube by centrifugal action.
A circumferentially positioned liquid outlet is provided in the vortex tube downstream of the vortex generator. This centrifugal outlet may be in the form of a circumferential slot formed in the vortex tube that can, in one practical embodiment, be achieved by forming the vortex tube of two axially aligned pipe sections wherein the section adjacent the outlet end of the vortex tube is of smaller internal diameter. As the gas stream flows within the vortex tube the liquid component is moved axially along the interior wall of the tube until the liquid encounters the circumferential liquid outlet. The liquid component is passed through the outlet while a substantial portion of the gas in the stream continues within the vortex tube to the tube outlet end.
As entrained liquid that has been forced against the interior wall of the vortex tube passes out through the circumferential liquid outlet a portion of the gas making up the stream also passes through the outlet, the discharged liquid and by-pass gas passing into the interspacial volume interior of the vessel, surrounding the tube.
A recycle port is provided in the vortex tube upstream of the vortex generator. The by-pass gas flowing into the interior of the vessel through the circumferential liquid outlet is drawn back into the interior of the vortex tube through the recycle port to co-mix with the gas stream entering the inlet end of the vortex tube.
In a preferred embodiment of the invention the interior of the separator vessel is compartmented to provide an inlet chamber, an outlet chamber and a middle chamber. Gas flowing out the outlet end of the vortex tube flows into the outlet chamber. This gas is relatively liquid-free compared to the wet gas that flows into the vessel inlet section. Liquid separated from the gas stream that flows out of the vortex tube through the circumferential liquid outlet passes into the middle chamber of the vessel and, by gravitational force, accumulates in a lower portion of the vessel and is withdrawn through the vessel liquid outlet.
In order to induce recirculation of the by-pass gas to flow back into the vortex tube a venturi effect is created in the vortex generator, creating a low static pressure. The venturi is preferably combined with the vortex generator. In the preferred embodiment the venturi/vortex generator is formed using a nosecone member having an external diameter less than the internal diameter of the vortex tube, and an aerodynamic forward end. The vortex generator or spin generator is accomplished by a plurality of spaced apart circumferentially arranged curved blades that extend between the exterior of the nosecone and the interior of the vortex tube. These curved blades are configured to impart a high rate of spin to gas passing through the vortex tube while, as above indicated, the nosecone member achieves venturi action. In the preferred arrangement the nosecone rearward portion is hollow, the hollow area communicating via an open rearward end of the nosecone with the fluid stream passing through the tube. A duct is provided between the by-pass return opening in the vortex tube so that recycled gas passes through the opening in the tube, through the duct and into the interior of the nosecone where it is discharged out the rearward end thereof back into the gas stream.
A better understanding of the invention will be obtained from the following description of the preferred embodiments taken in conjunction with the attached claims and with the attached drawings.